The Conservatives could be heading for a meltdown in tomorrow's election, threatening a fresh round of in-fighting over the future direction of the party.

The Conservatives could be heading for a meltdown in tomorrow's election, threatening a fresh round of in-fighting over the future direction of the party.

With 24 hours to go, Michael Howard learned the latest polls show the Tories have slumped to 27 per cent, Labour has increased to 41 per cent, and the Liberal Democrat share has increased to 23 per cent.

The findings came as a blow to Mr Howard on the eve of election day, and could lead to blood-letting over his negative campaign. If borne out on polling day, the Tories could lose seats in Parliament and leave Tony Blair with a bigger majority.

Senior Tories were pinning their hopes on the polls being proved wrong by a stronger Tory showing in marginal seats, helped by a massive abstention by Labour voters, registering a protest vote against Mr Blair.

However, the findings were in line with a MORI poll yesterday in the Financial Times showing the Tories on 29 per cent and Labour on 39 per cent.

Sandra Howard, in a rare interview last night aimed at bolstering Tory support among women, conceded that her husband had been feeling the strain from the campaign. The former model, who has avoided interviews until now, said on BBC radio she had "calmed down" Mr Howard "once or twice" during the campaign. "He has been pretty good. He has not got uptight too much which is always a danger when you are at full stretch," she said. "I get a bit upset but Michael has got quite broad shoulders," she said. Mrs Howard remained optimistic that the latest polls could be proved wrong.

"There are a huge number of people who simply have not made their minds up - not just saying that because they don't want to admit how they are going to vote. You sense there is everything to play for." Asked if she is ready to move in to Downing Street, she added: "One day at a time."

In spite of the devastating polls, senior Tories said Mr Howard would not resign on Friday but would stay on to oversee the inquest into the Tories' third defeat - the worst performance in their history - if it came into being.

Senior Tories rallied round the leader, saying he had pulled the party around since replacing Iain Duncan Smith. "We would have been a sick joke without Michael. He should not resign," said a former minister. Some shadow ministers are highly critical of the party's focus on immigration at the start of the campaign.

The blame for the Tories' likely third successive defeat - which would be the worst series of results in their history - is being levelled by Tory candidates at the so-called "Notting Hill set", the young advisers around Mr Howard, including Rachel Whetstone, 37, his political adviser.

Mr Howard's "kitchen cabinet" is already being criticised by senior Tories for advising the party leader against offering ambitious headline-grabbing tax cuts. "There will have to be an inquest about the failure to offer more on tax cuts," said one veteran Tory yesterday. "I've had no effect on the leadership campaign because I'm not Rachel Whetstone."

Tory campaigners in the Midlands reported to headquarters that they had failed to win back voters captured by Mr Blair in 1997 but they are doing far better on the ground than the polls suggest because of a big abstention by "Old Labour" voters.

In a clear sign of dissatisfaction with the Tory campaign, The Independent has learned that some shadow ministers are refusing to use immigration in their campaign leaflets.

They include Tim Yeo, the shadow Environment Secretary, who is on the centre-left of the party and defending Suffolk South. He said: "It's certainly true I have put on my campaign literature the issues I think are most important to my constituents."

Andrew Lansley, the shadow Health Secretary, does not include any reference to immigration in Cambridgeshire South, where the non-white population is less than 2 per cent. He said: "My election address focuses on local issues including wind farms, a children's hospital, NHS deficits and council tax."

Meanwhile, the party faced accusations of making a "racist slur" in its manifesto from a leading member of the Sikh community. Jagjit Taunque, who is the Deputy Lord Lieutenant of the West Midlands, protested over the depiction of a Sikh man getting out of a van with the word "Imports" across its side.

Dr Taunque said: "The Tories cannot conceal their contempt for members of ethnic communities. They show their ignorance when they portray Sikhs as new arrivals to the UK when in fact we fought in the British Army wearing our turbans."